Many sensors provide information in the form of a time-varying resistance. For example, a thermistor is a type of resistor whose resistance varies significantly with temperature. Thermistors are widely used as inrush current limiters, temperature sensors, self-resetting overcurrent protectors, and self-regulating heating elements. A resistance temperature detector (RTD) is another example of a sensor that provides information in the form of a time-varying resistance. RTDs differ from thermistors in that the material used in a thermistor is generally a ceramic or polymer, while an RTD uses pure metals.
Moreover, sensors that provide a time-varying resistance are not limited to those where resistance varies with temperature; and other ambient environmental conditions can also be measured by sensors that use a time-varying resistance. For example, pressure can be measured by pressure transducers, such as in the form of piezoelectric sensors. The piezoresistive effect describes change in the electrical resistivity of a semiconductor when mechanical stress is applied.
Whatever the exact condition being measured, it is important to accurately measure the resistance value of resistors in order to accurately determine the corresponding ambient environmental condition. The present disclosure provides improved techniques for determining such resistance values.